Accessing table row items by row and column header names

Hi,
I'd like to set/get some of a table items by using its row and column header names, in order to make my code more readable and maintenable.
If tbl is my table, and rowXHeaderName, colYHeaderName are variables containing my row X and column Y header names, I'd like to achive something like that:

tbl.DataBodyRange(tbl.ListRows(rowXHeaderName).Index, tbl.ListColumns(colYHeaderName).Index) = myItemXY
But this gives me a "subscript out of range" error, while

tbl.DataBodyRange(1, tbl.ListColumns(columnYHeaderName).Index) = myItemXY
Works.

So I understand that the header name can't be used in the same way as for the columns.

Any idea?
Thank you,
Margie